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Orthogonality of silver‐ion and non‐aqueous reversed‐phase HPLC/MS in the analysis of complex natural mixtures of triacylglycerols
Author(s) -
Holčapek Michal,
Velínská Hana,
Lísa Miroslav,
Česla Petr
Publication year - 2009
Publication title -
journal of separation science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.72
H-Index - 102
eISSN - 1615-9314
pISSN - 1615-9306
DOI - 10.1002/jssc.200900401
Subject(s) - chemistry , mass spectrometry , chromatography , high performance liquid chromatography , analytical chemistry (journal) , selectivity , aqueous solution , atmospheric pressure chemical ionization , structural isomer , ion , reversed phase chromatography , two dimensional chromatography , ionization , chemical ionization , organic chemistry , catalysis
The goal of this work is the study of possibilities of two basic separation modes used in the analysis of complex triacylglycerol (TG) samples of plant oils and animal fats, i.e. non‐aqueous reversed‐phase (NARP) and silver‐ion HPLC coupled with atmospheric pressure chemical ionization mass spectrometry (APCI‐MS). The orthogonality of both separation modes is tested for complex TG mixtures containing fatty acids (FAs) with different acyl chain lengths, different number, positions and geometry of double bonds (DBs) and different regioisomeric positions of FAs on the glycerol skeleton. The retention in NARP mode is governed by the equivalent carbon number, while the retention in silver‐ion chromatography increases with the increasing number of DBs with a clear differentiation between cis ‐ and trans‐ FAs. Moreover, silver‐ion mode enables at least the partial resolution of regioisomeric TG mixtures including cis ‐/ trans ‐regioisomers, as illustrated on two examples of randomization mixtures. Off‐line 2D coupling of both complementary modes (NARP in the first dimension and silver‐ion in the second dimension) yields the superior chromatographic selectivity resulting in the highest number of identified TGs ever reported for studied samples. Off‐line 2D chromatograms are processed with the home‐made software providing various ways of data visualization.